How it grew: Thrillist, the city and lifestyle site for men, was already profitable, raking in $7 million in annual revenue from advertising and subscriptions, when it bought Columbus, Ohio-based men’s online clothing retailer Jack Threads. The leap into commerce triggered a whole new phase of growth for the company, which has a presence in 17 U.S. cities and in London. Today, commerce accounts for 60% of Thrillist’s sales and has helped make it the third fastest-growing company in the Crain’s Fast 50.

“Once we put the commerce infrastructure around the content infrastructure, we had a much more robust and scalable model,” said CEO and co-founder Ben Lerer.

Next up: a private-label clothing line, more commerce and a new pop-up edition for Atlantic City, N.J. This spring, Thrillist launched Goodale, a line of streetwear designed to appeal to its target audience, 18- to 34-year-old men. Mr. Lerer is also noodling the possibility of expanding overseas, as well as other opportunities to sell merchandise and broaden content and advertising in lucrative categories, such as automobiles, fashion and financial services.

“We’re doing the build-or-buy analysis around these verticals,” said Mr. Lerer. “Are there existing properties we can fold into Thrillist Media Group, or build our own stuff or enter into partnerships?”